ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Digitale Medien

Reflectance anisotropy spectroscopy study of the surface reconstructions of decapped InP(001) (1998)

Johal, T. K. ; Barrett, S. D.

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 83 (1998), S. 480-485

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7550

Quelle: AIP Digital Archive

Thema: Physik

Notizen: A reflectance anisotropy spectroscopy (RAS) and low-energy electron diffraction study of the InP(001) surface is presented. The surface was prepared by thermal desorption of an As-P capped epilayer grown by molecular beam epitaxy. RA spectra have been monitored over a spectral range of 1.5–5.5 eV at regular intervals during thermal decapping and annealing up to the point of decomposition (553–973 K). Each of the RA spectra of the surface reconstructions comprise positive (at 2.9 eV) and negative (at 1.8 eV) anisotropies which have been previously associated with P- and In-related bonding, respectively. Unlike other III-V (001) semiconductor surfaces, the evolution of different reconstructions cannot be explained in terms of a change in surface stoichiometry which involves loss of the anion species. In the case of InP(001) the P species contributes to the clean surface reconstruction from the early stages of decapping to the point of decomposition. © 1998 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.366718

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

2

Digitale Medien

IX.—Descriptions of New Species of Fossils, from the Upper Silurian Rooks of Port Jervis, N. Y.; with Notes on the occurrence of the Goralline Limestone at that Locality (1879)

BARRETT, S. T.

Oxford, UK : Blackwell Publishing Ltd

Annals of the New York Academy of Sciences 1 (1879), S. 0

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1749-6632

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Allgemeine Naturwissenschaft

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1111/j.1749-6632.1879.tb55114.x

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

3

Digitale Medien

The Microphone (1878)

BARRETT, S. T.

[s.l.] : Nature Publishing Group

Nature 18 (1878), S. 540-540

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1476-4687

Quelle: Nature Archives 1869 - 2009

Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik

Notizen: [Auszug] THE form of microphone described by Mr. Gerald B. Francis (NATURE, vol. xviii. p. 383) is easily made and very efficient. It not only did for me all its inventor promised, but with a common tumbler inverted over it upon the sounding-board so as to prevent direct impact of sound waves upon the ...

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1038/018540d0

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

4

Digitale Medien

Utilization of Photoemission Cross-Section Effects for Monitoring Thin-Film Growth in UHV (1995)

Tucker, N. P. ; Blyth, R. I. R. ; White, R. G. ; [weitere]

Chester : International Union of Crystallography (IUCr)

Journal of synchrotron radiation 2 (1995), S. 252-255

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1600-5775

Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001

Thema: Geologie und Paläontologie , Physik

Notizen: Given the tunability of synchrotron radiation, photoemission spectroscopy can be used to monitor the growth modes of thin films in UHV. Cross-section effects such as Cooper minima and resonant photoemission can be exploited to maximize the adsorbate signal and minimize that from the substrate. Under favourable circumstances growth can be monitored in real time at coverages of 〈1%. As an example the growth of Gd on W(110) is investigated.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1107/S0909049595008697

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

5

Digitale Medien

Gd/W(110) Interface Formation Studied by W 4f Surface Core-Level Spectroscopy (1995)

White, R. G. ; Blyth, R. I. R. ; Tucker, N. P. ; [weitere]

Chester : International Union of Crystallography (IUCr)

Journal of synchrotron radiation 2 (1995), S. 261-263

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1600-5775

Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001

Thema: Geologie und Paläontologie , Physik

Notizen: W 4f core-level spectra of Gd films on W(110) show components which can be identified as being due to bulk and interface W. The results suggest that the W/Gd interface is abrupt, i.e. no interface alloying occurs. At submonolayer coverages a further component is seen which is attributable to intermediate (n × 2) phases.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1107/S090904959500954X

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

6

Digitale Medien

Ice Crystals and Filaments (1880)

BARRETT, S. T.

[s.l.] : Nature Publishing Group

Nature 21 (1880), S. 537-537

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1476-4687

Quelle: Nature Archives 1869 - 2009

Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik

Notizen: [Auszug] SOMETHING very like the “comb-like masses of ice” appears upon the surfaces of plaster-models such as dentists make, after they have been coated with a preparation called Liquid Silex; except that it is finer and woolly. It seems to be caused by the contraction of the models forcing out very ...

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1038/021537c0

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

7

Digitale Medien

Photoemission Study of CO Adsorption on Gd (1995)

Searle, C. ; Blyth, R. I. R. ; White, R. G. ; [weitere]

Chester : International Union of Crystallography (IUCr)

Journal of synchrotron radiation 2 (1995), S. 312-315

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1600-5775

Quelle: Crystallography Journals Online : IUCR Backfile Archive 1948-2001

Thema: Geologie und Paläontologie , Physik

Notizen: Angle-resolved UV photoemission spectroscopy has been used to investigate the interaction of CO with Gd films, grown on W(110). The results suggest the CO absorbs dissociatively, initially forming Gd2O3, with subsequent catalytic oxidation of CO to form carbonate.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1107/S090904959501137X

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

8

Digitale Medien

Variation of pollen limitation in the early flowering Mediterranean geophyte Narcissus assoanus (Amaryllidaceae) (2000)

Baker, A. M. ; Barrett, S. C. H. ; Thompson, J. D.

Springer

Oecologia 124 (2000), S. 529-535

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1432-1939

Schlagwort(e): Key words Fruit and seed set ; Narcissus assoanus ; Pollen limitation ; Reproductive ecology ; Seed:ovule ratios

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract A recent literature review indicates that pollen limitation of female fertility is a common feature of flowering plants. Despite the ecological and evolutionary significance of pollen limitation, most studies have only examined fertility in a single population at one time. Here we investigate pollen limitation of fruit and seed set in five populations of Narcissus assoanus, a self- sterile, insect-pollinated geophyte, over 2–3 years in southern France. In common with many early spring flowering plants, pollinator visitation to N. assoanus is often infrequent. Supplemental hand-pollination of flowers with outcross pollen significantly increased overall fruit and seed set by 11% and 19%, respectively. Four of the five populations experienced some pollen limitation during the study. For a given year, there was significant variation in pollen limitation among populations. Two of the populations were pollen limited in one year but not in other years in which they were studied. Seed:ovule ratios for open- and hand-pollinated flowers averaged 0.29 and 0.33, respectively. While hand pollination significantly increased the seed:ovule ratio, the low value obtained indicates that the majority of ovules in flowers do not mature seeds despite hand pollination. The role of genetic and environmental factors governing low seed:ovule ratios in N. assoanus is discussed.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/s004420000417

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

9

Digitale Medien

Trimorphic incompatibility in Eichhornia azurea (Pontederiaceae) (2000)

Bianchi, M. ; Vesprini, J. ; Barrett, S. C. H.

Springer

Sexual plant reproduction 12 (2000), S. 203-208

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1432-2145

Schlagwort(e): Key words Tristyly ; Trimorphic incompatibility ; Pollen trimorphism ; Partial incompatibility ; Clonal aquatic plant

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract Eichhornia azurea (Pontederiaceae) is a mat-forming, clonal aquatic that inhabits lakes, marshes and river systems in many parts of the Neotropics. The species is tristylous with long-, mid-, and short-styled morphs commonly represented in natural populations. To investigate whether E. azurea possesses a trimorphic incompatibility system typical of tristylous species, we conducted a controlled pollination experiment on 15 clones representing the three style morphs from a natural population near Rosario, Argentina. Comparisons of fruit and seed set following self-, illegitimate, and legitimate pollinations clearly demonstrated the presence of trimorphic incompatibility in E. azurea. Self- and illegitimate pollinations produced significantly less fruit and seed than legitimate pollinations in all three style morphs. Pollen from the two anther levels within a flower exhibited contrasting compatibility relations in self-pollinations. In common with several other tristylous species in Pontederiaceae, the expression of self-incompatibility was weakest in the mid-styled morph and strongest in the short-styled morph. We discuss the ecological and evolutionary significance of the partial expression of trimorphic incompatibility in E. azurea.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/s004970050001

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

10

Digitale Medien

Heterostyly in the Lamiaceae: The case ofSalvia brandegeei (2000)

Barrett, S. C. H. ; Wilken, D. H. ; Cole, W. W.

Springer

Plant systematics and evolution 223 (2000), S. 211-219

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1615-6110

Schlagwort(e): Heterostyly ; distyly ; zygomorphic flowers ; self-compatibility ; protandry ; geitonogamy ; Lamiaceae ; rare plant species

Quelle: Springer Online Journal Archives 1860-2000

Thema: Biologie

Notizen: Abstract Heterostyly rarely occurs in families with strongly zygomorphic flowers. For this reason Darwin (1877) doubted whether heterostyly would occur in the Lamiaceae and recent reviews have not reported the floral polymorphism in this family. Here we describe distyly in a rare species ofSalvia restricted to bluffs and seaward canyons on Santa Rosa Island (Santa Barbara Co., California) and northwestern Baja California (Mexico).Salvia brandegeei is morphologically distylous with populations composed of equal frequencies of long-and short-styled morphs differing reciprocally in stigma and anther position. Controlled hand pollinations demonstrated no significant differences in the seed set of self, intramorph or intermorph pollinations. Unlike most heterostylous species investigated,S. brandegeei does not possess diallelic incompatibility or ancillary polymorphisms of pollen and stigmas. We propose that the evolution of distyly inS. brandegeei may have been associated with an ecological shift to a new environment in which protandry failed to prevent increased levels of geitonogamy. Heterostyly was then selected because it increased the proficiency of cross-pollination. The origin of distyly in self-compatibleS. brandegeei is consistent with Lloyd and Webb's theoretical model for the evolution of distyly.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF00985280

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext